Definition and Overview

Knee swelling occurs when fluid builds up in the tissues surrounding the knee joint or within the joint capsule itself. This can result from acute injuries, chronic conditions, infections, or systemic diseases. The knee, being one of the largest and most complex joints in the body, is particularly susceptible to various conditions that can cause swelling.

The swelling may develop rapidly within hours of an injury or gradually over days to weeks with chronic conditions. It can affect one or both knees and may be accompanied by other symptoms such as pain, stiffness, warmth, and difficulty bearing weight. The amount of swelling can range from mild puffiness to severe enlargement that significantly limits knee movement.

Understanding the pattern, timing, and associated symptoms of knee swelling is crucial for proper diagnosis and treatment. While some causes are relatively minor and resolve with conservative treatment, others may indicate serious conditions requiring immediate medical attention or long-term management.

Common Causes

Traumatic Injuries

Inflammatory Conditions

  • Osteoarthritis: Wear-and-tear arthritis
  • Rheumatoid arthritis: Autoimmune condition
  • Gout: Crystal-induced arthritis
  • Pseudogout: Calcium crystals
  • Bursitis: Bursa inflammation
  • Psoriatic arthritis: Skin condition related
  • Reactive arthritis: Post-infection
  • Lupus: Systemic autoimmune

Other Causes

Associated Symptoms

Local Symptoms

  • Knee pain
  • Stiffness and reduced motion
  • Warmth over the knee
  • Redness or skin changes
  • Feeling of instability
  • Clicking or popping sounds
  • Difficulty bending or straightening
  • Visible deformity

Functional Problems

  • Difficulty walking
  • Unable to bear weight
  • Limping gait
  • Problems climbing stairs
  • Can't fully extend knee
  • Knee giving way
  • Night pain disrupting sleep
  • Morning stiffness

When to Seek Medical Attention

Seek immediate medical care for:

  • Sudden severe swelling after injury
  • Inability to bear weight on the knee
  • Obvious deformity or bone out of place
  • Signs of infection (fever, red, hot knee)
  • Severe pain not relieved by rest
  • Numbness or tingling below the knee
  • Cold or blue foot (circulation problem)
  • Knee locked in one position
  • Rapid swelling with no apparent cause
  • History of blood clots with new swelling
  • Multiple joints swollen

Diagnostic Approach

Healthcare providers evaluate knee swelling through:

Diagnostic Methods

  • Physical examination: Palpation, range of motion
  • X-rays: Bone fractures, arthritis
  • MRI: Soft tissue injuries
  • Ultrasound: Fluid detection, cysts
  • CT scan: Complex fractures
  • Arthrocentesis: Joint fluid analysis
  • Blood tests: Infection, inflammation markers
  • Arthroscopy: Direct visualization

Treatment and Management

RICE Protocol

  • Rest: Avoid activities that worsen swelling
  • Ice: 15-20 minutes every 2-3 hours
  • Compression: Elastic bandage (not too tight)
  • Elevation: Raise knee above heart level
  • Use crutches if needed
  • NSAIDs for pain and inflammation
  • Gentle range of motion exercises
  • Avoid prolonged sitting or standing

Medical Treatments

  • Joint aspiration (fluid removal)
  • Corticosteroid injections
  • Hyaluronic acid injections
  • Physical therapy
  • Antibiotics for infection
  • Disease-modifying drugs for arthritis
  • Surgery for structural problems
  • Arthroscopic procedures

Prevention

Reduce your risk of knee swelling:

  • Maintain healthy weight: Reduce joint stress
  • Strengthen muscles: Quadriceps and hamstrings
  • Warm up properly: Before exercise
  • Use proper technique: In sports and activities
  • Wear supportive shoes: Good cushioning
  • Avoid overuse: Gradual activity increases
  • Cross-training: Vary activities
  • Protective gear: For contact sports
  • Stay flexible: Regular stretching
  • Manage chronic conditions: Arthritis, gout